Method for joining blades to blade roots or rotor disks when manufacturing and/or repairing gas turbine blades or integrally bladed gas turbine rotors

Abstract

A method is provided for joining blades to blade roots or rotor disks when manufacturing and/or repairing gas turbine blades or integrally bladed gas turbine rotors. A blade and a blade root or rotor disk that is to be joined to the blade are supplied, and provided with a thickening in sections that are to be joined together. The sections of the blade and the blade root or rotor disk that are to be joined together are machined so as to form recesses and; c) are then aligned relative to each other, opposite recesses defining at least one groove-shaped seam preparation. The blade and the blade root or rotor disk are joined in the area of the or each seam preparation by means of laser power build-up welding and the joined blade and blade root or rotor disk are machined so as to provide a gas turbine blade or an integrally bladed gas turbine rotor having a predefined geometrical profile.

1. A method for joining blades to blade roots or rotor disks when manufacturing and/or repairing gas turbine blades or integrally bladed gas turbine rotors, comprising:
 a) prefabricating a blade and a blade support to be joined to the blade, the blade support being one of a blade root and a rotor disk, the blade having a thickened region at a portion of the blade to be joined to the blade support, the blade support having a thickened region at a portion of the blade support to be joined to the blade; 
 b) machining said portion of the blade and said portion of the blade support to form recesses; 
 c) subsequently mutually aligning the blade and the blade support to be joined to the blade such that said recesses form mutually opposing recesses delimiting at least one groove-shaped weld preparation; 
 d) joining the blade and the blade support in an area of the at least one groove-shaped weld preparation by employing laser powder build-up welding; 
 e) machining the joined blade and blade support to form a gas turbine blade or an integrally bladed gas turbine rotor having a predefined geometric profile. 
 
   
   
     2. The method as recited in  claim 1 , wherein the recesses extend between a flow inlet edge and a flow outlet edge of the blade and over an entire axial length of the blade. 
   
   
     3. The method as recited in  claim 1 ,
 wherein, after the alignment step, the recesses extend both on an intake side of the blade and a thrust side of the blade, and 
 wherein, during the joining step, the laser powder build-up welding is performed simultaneously on the intake side and the thrust side. 
 
   
   
     4. The method as recited in  claim 1 ,
 wherein, after the alignment step, the recesses extend on only one side of the blade, said one side being either an intake side of the blade or a thrust side of the blade, and 
 wherein, during the joining step, the laser powder build-up welding is performed on said one side. 
 
   
   
     5. The method as recited in  claim 4 , comprising,
 after the joining step, forming another groove-shaped weld preparation on the other side of the blade such that any nicks and/or imperfections in the area of a root of the weld seam already formed by laser powder build-up welding are removed; and 
 subsequently thereto, and before the machining step, performing a laser powder build-up welding process in an area of said another groove-shaped weld preparation on the other side. 
 
   
   
     6. The method as recited in  claim 1 , wherein said machining step is performed via a milling process. 
   
   
     7. A method for repairing gas turbine blades or integrally bladed gas turbine rotors, comprising:
 a) performing laser powder build-up welding to form a thickened region at least in a separating region of a damaged blade; 
 b) separating the damaged blade from a gas turbine along the separating region to form a blade support, the blade support being one of a blade root and a rotor disk, the blade support having a portion of the thickened region formed in step (a); 
 c) prefabricating a replacement blade, the replacement blade having a thickened region at a portion of the replacement blade to be joined to the blade support; 
 d) machining said portion of the replacement blade and said portion of the blade support to form recesses; 
 e) subsequently mutually aligning the replacement blade and the blade support to be joined to the replacement blade such that said recesses form mutually opposing recesses delimiting at least one groove-shaped weld preparation; 
 f) joining the replacement blade and the blade support in an area of the at least one groove-shaped weld preparation by employing laser powder build-up welding; 
 g) machining the joined blade and blade support to form a gas turbine blade or an integrally bladed gas turbine rotor having a predefined geometric profile. 
 
   
   
     8. The method as recited in  claim 7 , wherein the recesses extend between a flow inlet edge and a flow outlet edge of the replacement blade and over an entire axial length of the replacement blade. 
   
   
     9. The method as recited in  claim 7 ,
 wherein, after the alignment step, the recesses extend both on an intake side of the replacement blade and a thrust side of the replacement blade, and 
 wherein, during the joining step, the laser powder build-up welding is performed simultaneously on the intake side and the thrust side. 
 
   
   
     10. The method as recited in  claim 7 ,
 wherein, after the alignment step, the recesses extend on only one side of the replacement blade, said one side being either an intake side of the replacement blade or a thrust side of the replacement blade, and 
 wherein, during the joining step, the laser powder build-up welding is performed on said one side. 
 
   
   
     11. The method as recited in  claim 10 , comprising,
 after the joining step, forming another groove-shaped weld preparation on the other side of the replacement blade such that any nicks and/or imperfections in the area of a root of the weld seam already formed by laser powder build-up welding are removed; and 
 subsequently thereto, and before the machining step, performing a laser powder build-up welding process in an area of said another groove-shaped weld preparation on the other side. 
 
   
   
     12. The method as recited in  claim 7 , wherein said machining step is performed via a milling process.